Ship hulls are subjected to water resistance forces that lower ship performance and increase energy consumption. Wave making resistance and viscous drag represent the most important loss of energy during ship motion.
Wave making resistance reflects the energy required to displace the water in front of the ship. This energy is transmitted to the water and creates waves along the ship path. Viscous drag is a frictional force opposed to ship motion. In order to save energy and improve ship performance, a number of solutions for reducing hull resistance forces have been developed. Some of these solutions attempt to use bulbous extensions to marginally reduce wave making resistance. Other solutions attempt to use air bubble injection to reduce viscous drag. Some solutions are based on the use of external propellers on the sides of the hull in order to use front water to propel the ship.
Other solutions consist of flowing water from the front of the ship to the rear part of the ship in order to decrease the water resistance on the ship hull. For example, WO20100037253 discloses a flow conduit that communicates a forward water intake opening with a backward water discharge opening provided at the stern or at the two sides of the hull. A water communicating pipeline can also guide water from the front part of the ship to the rear part of the ship, as described in CN2350310. A screw propeller is therefore positioned at the rear part of the ship in the water communicating pipeline. In CN102285440, the displaced water is propelled through draft tubes at the rear of the ship. In a same manner, in CN101209751, a water inlet is arranged at a bow and a water outlet is arranged at a stern such that a pipeline guides water through the front and back of a ship body. WO1992022456 discloses an external conduct mounted forward of the bow and extending to the aft of the ship. In JP2014522778 a hydrodynamic duct is attached to the bow of a ship. Water flows through the duct, wave making effects and frictional resistance are reduced. In WO1982003055, the vessel has a duct through which water flows from the bow to the stern past the main part of the hull. According to WO1982003055, part of the water flows past the vessel through a duct and is used to assist forward motion of the vessel. However, none of the above mentioned document teaches features that allow for water flow control and water pressure control at different areas of the ship hull. Moreover, these solutions fail to meet the needs of industry because they alter specific aspects of optimum hull design and produce marginal results that sometime do not compensate for the complexity of integrating such solutions in the manufacturing process.
Therefore, there currently exists a need in the industry for a ship design that can eliminate the hydrodynamic resistance of wave making and viscous drag, and improve the maneuverability and sea keeping characteristics of a ship while minimizing the operational cost and the alteration of an optimum hull design.
Furthermore, it would be desirable to have a solution for the aforementioned desirable features that can be retrofitted on existing ships.